Water Quality and Common Treatments for Private Drinking Water Systems (B 939)

Revised by Uttam Saha, Leticia Sonon, Mark Risse1 and David Kissel
Agricultural and Environmental Services Laboratories1Department of Biological and Agricultural Engineering
Originally written by Anthony Tyson and Kerry Harrison, Extension Engineers

Introduction

An abundant supply of clean, safe drinking water is
essential for human and animal health. Water from
municipal or public water systems is treated and
monitored to ensure that it is safe for human consumption.
Many Georgia residents, especially in rural areas,
rely on private water systems for human and livestock
consumption. Most private water systems are supplied
by wells.

Water from wells in Georgia is generally safe for consumption
without treatment. Some waters, however,
may contain disease-causing organisms that make
them unsafe to drink. Well waters may also contain
large amounts of minerals, making them too “hard”
for uses such as laundering, bathing or cooking. Some
contaminants may cause human health hazards and
others can stain clothing and fixtures, cause objectionable
tastes and odors, or corrode pipes and other
system components.

Surface water sources, such as springs and cisterns,
are seldom used for drinking water. They are almost
always contaminated with pathogenic microorganisms;
therefore, surface water should always be treated
before being consumed.

The quality of drinking water from private sources is
the responsibility of the homeowner. State laws do not
require testing of private domestic water supplies, and
regulatory agencies do not regularly monitor the quality
of water from private supplies. Therefore, the only
way homeowners can be certain that their water is safe
to drink is to have it tested periodically.

Drinking Water Standards

The EPA standards for drinking water fall into two categories:
Primary Standards and Secondary Standards.
The current standards for some selected primary and
secondary contaminants are listed below in Tables 1
and 2. For further details about EPA’s drinking water
standards, visit http://water.epa.gov/drink/contaminants/
index.cfm#List.

Primary Drinking Water Standards

Primary Standards are based on health considerations
and are enforced by the EPA in public water systems.
They protect you from three classes of toxic pollutants:
microbial pathogens, radioactive elements and
organic/inorganic chemicals. Many of these contaminants
occur naturally in trace amounts in ground or
surface water. Primary Standards set a limit, called the
Maximum Contaminant Level (MCL), which is the
highest allowable concentration of a contaminant in
drinking water supplied by public water systems. The
MCL is an enforceable health goal based on calculated
risk due to exposure for a period of time. For example,
EPA calculates health risk for arsenic based on assumption
that an individual would drink from a singular
water source for 70 years. Besides MCL, Primary
Standards set another limit, called Maximum Contaminant
Level Goal (MCLG), the level of a contaminant
in drinking water below which there is no known
or expected risk to health. MCLGs allow for a greater
margin of safety than MCLs, but these are non-enforceable
public health goals. Both MCL and MCLG
are usually expressed in milligrams per liter (mg/L) or
parts per million (ppm), which are numerically equivalent.
Table 1 lists the current primary drinking water
standards, including organic/inorganic chemicals,
radioactive elements and microbial pathogens.

a Although there is no collective MCLG for this contaminant group, there are individual MCLGs for some of the individual contaminants: bromodichloromethane (zero); bromoform (zero); dibromochloromethane (0.06 mg/L): chloroform (0.07mg/L).b Concentrations of radioactive elements are measured in picocuries per liter (pCi/L), a measure of radioactivity.c ‘Colony Forming Units (CFU)’ or ‘Most Probable Number (MPN)’ in a 100 milliliter sample of water.d Turbidity is a measure of the cloudiness of water. It is used to indicate water quality (e.g., whether disease-causing organisms are present) and filtration effectiveness. Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria. These organisms can cause symptoms such as nausea, cramps, diarrhea and associated headaches.e Not available.

Secondary Drinking Water Standards

Secondary Drinking Water Standards regulate constituents
that cause offensive taste, odor, color, corrosivity,
foaming and staining. The concentration limit
is called the Secondary Maximum Contaminant Level
(SMCL). Secondary Standards are not enforceable.
Public water systems are not required to test for or
remove secondary contaminants. Secondary Standards
are guidelines for water treatment plant operators and
state governments attempting to provide communities
with the best quality water possible. See Table 2 for
Secondary Drinking Water Standards, including inorganic
chemicals and physical problems.

15 color units
noncorrosive
3 TON (threshold odor number)
Not less than 6.5 and not greater than 8.5 on pH scale

Water Testing

To ensure that water is safe for human consumption
and livestock use, water supplies should be tested and
checked to ensure they meet the acceptable levels for
bacterial and chemical contents.

The local health department in most counties can conduct
a microbiological test. The University of Georgia
Cooperative Extension can conduct both microbiological
and chemical or mineral analysis. Many private
laboratories also offer these tests. To test your water,
call your local county Extension office (1-800-ASKUGA1)
or check with your municipal water supplier
or county health department to find a certified private
laboratory near you. A list of water testing laboratories
certified by Georgia Department of Natural Resources
is also available at: http://agr.georgia.gov/ (pdf).

The testing procedure is not the same for all contaminants.
Call your local Extension office, health department
or private lab for appropriate bottle(s) and instructions
on sample collection and submission. After
sending a water sample to a laboratory, the laboratory
will then return a report indicating what is found in
your water, including those contaminants that exceed
standard levels (MCLs or SMCLs). Treatment options
are also recommended when necessary.

Specific questions about water quality can often be
answered with the right test. Unfortunately, no single
water test can provide you with information on all
possible contaminants. Public water supply systems
typically spend few thousand dollars to analyze for the
EPA-required suite of all primary and secondary contaminants
that may be found in drinking water. Such
a comprehensive testing is expensive, impractical and
may not be necessary for a domestic well. Instead,
tests for some common constituents are recommended
as discussed below.

Mineral Analysis

A mineral analysis checks for the inorganic constituents
found in water. A typical mineral analysis will
give the content in parts per million (milligrams per liter)
of mineral elements such as calcium, magnesium,
manganese, iron, copper and zinc. It will also determine
the acidity or pH of the water and the hardness,
expressed in parts per million or grains per gallon. It
may also give the concentration of nitrate, sulfates and
other chemical compounds.

Large amounts of minerals and other impurities may
pose a health hazard. For instance, nitrate contamination
can cause health problems for infants and ruminant
animals, sulfates can have a laxative effect in
humans, and arsenic may cause cancer if consumed
over a long period of time. Minerals at high concentrations
can also affect the appearance and use of the
water. Hard water is due to high levels of calcium and
magnesium. Iron may leave red stains on plumbing
fixtures, equipment and laundry. Suspended silt makes
water look muddy or cloudy and dissolved gases may
give water a bad taste and/or odor.

Microbiological Tests

A microbiological test tells you if your water is at risk
for contamination by disease-causing microorganisms
(pathogens). However, testing drinking water for
all possible pathogens is complex, time consuming
and expensive. Instead, water is commonly tested for
indicator microorganisms such as total coliform and E.
coli bacteria because if they are present in water, the
condition of the well and its surrounding environment
may support the presence of other disease-causing
microorganisms. Thus, a positive water test result for
total coliform only or both total coliform and E. coli
indicate the possible existence of various disease-causing
microorganisms.

Coliform is a group name that includes many bacteria.
Most coliform bacteria do not cause disease and they
are abundant in soils, waters, vegetation, etc. However,
their presence in drinking water indicates that
disease-causing organisms could be contaminating
the water system. E. coli is a special type of coliform
bacteria that most likely originates from a fecal
source. Most E. coli bacteria are also harmless and are
found in great quantities in the intestines of people and
warm-blooded animals. However, some E. coli strains
(for example E. coli O157:H7) can cause illness. The
presence of E. coli in a drinking water sample almost
always indicates recent fecal contamination by sewage
or manure, meaning there is a greater risk that pathogens
are present. For further information about coliform
bacteria, refer to University of Georgia Cooperative
Extension Circular 858-7, Your Household Water
Quality: Coliform Bacteria in Your Water.

Pesticide and Other Organic Chemical Tests

There are many man-made chemicals that can potentially
contaminate a water supply if they are not
disposed of properly. These chemicals may impair
water quality and cause a health hazard. Examples of
these chemicals include petroleum products, industrial
chemicals and agricultural pesticides.

Chemicals that are not part of a laboratory’s routine
suite of analysis are not typically analyzed unless a
particular type of chemical is suspected to be in the
water. It can be very expensive to test for the presence
of many unknown chemical contaminants; however, if
a particular chemical is suspected, a test can usually be
performed at a moderate cost.

UGA’s Recommended Guidelines for Testing Drinking Waters

The University of Georgia Water Testing Laboratory
recommends the following guidelines for testing
drinking waters.

Household Drinking Well Water

Expanded Water Test (W2): Designed to address
common well water problems in Georgia
such as corrosion and scaling, high levels of iron
and manganese, saltwater intrusion and nitrate
from various sources. It is also useful for water
treatment design. This test includes:

This test package should be done at least once
initially before using a less inclusive test package
such as W1. It should be repeated once every
three years.

Basic Water Test (W1): Recommended annually
only after an initial W2 has been conducted.

Total Coliform/E. coli (W35): Annually

Lead (W9): Initial + semi-annually. If your
house was built before 1985, pipes could contain
lead solder, which could leach into your drinking
water. However, if your home is piped with PVC
(as found in newer construction) and if the initial
testing does not show any concern about lead
there is no need for subsequent testing.

Hydrogen Sulfide: If your water smells like rotten
eggs.

Small Drinking Water Providers (Small Distribution Systems)

W33 and W35: W33 is a test designed for Georgia
Certification for Drinking Water Providers (Small Distribution
Systems). This includes:

Basic Water Test (W1) and anions (W3)

Total Nitrate (NO3-N) + Nitrite (NO2-N) Basic
Water Test (W1)

Nitrite-Nitrogen

Soluble Salts

Alkalinity

Total Dissolved Solids

Color

Turbidity

Collecting a Water Sample

Before collecting water for testing, contact the laboratory
or agency that will perform the test. They should
be able to provide you with a set of instructions and an
appropriate container(s) for sample collection.

Make sure you collect the sample from a faucet that
has had the aerator removed. Some tests require a first
draw water sample, whereas others require flushing of
the faucet and the pipes by running water for several
minutes before sampling. Collect the sample, making
sure not to touch the inside of the bottle or let the water
run over your hand before entering the bottle. Cap
the bottle immediately and deliver it to the laboratory
as quickly as possible. Note that the samples for some
water tests are required to be analyzed within a certain
specified period after collection, called holding time.
Your laboratory should provide you the information
about holding time requirements (if any).

To ensure that a well water supply is safe, it should
be tested for bacteria and nitrates at least once a year.
A complete mineral analysis (equivalent to W2 of the
UGA water testing laboratory) should be performed at
least every three years.

Figure 2: Water sampling for microbiological testing. Remove
the aerator from the faucet before collecting
the sample. Collect a water sample in a sterile container
and cap immediately. (Bottom Left): Sterile
bottle with tamper-proof seal. Contains white powder - DO
NOT REMOVE. (Photos: authors)

A simplified sampling protocol for the major drinking water tests offered by the University of Georgia’s Water
Laboratory is given below (Table 3).

Table 3. A simplified sample collection protocol for some major drinking water tests available at UGA’s water testing laboratory.

Tests

Bottle: Size and Type

Sampling

W1: Basic Water Test
(pH, minerals and hardness)

125 mL Plastic
(4 oz.)

Collection Spot:
A kitchen faucet or a faucet used most often for drinking and cooking.

Protocol:
1. A first draw water sample will be collected either early morning or evening upon returning home to ensure that the necessary 6-12 h stagnant water conditions exist.

2. Place a clean sample container below the faucet and gently open the cold water tap. Completely fill all sample bottles, being careful not to contaminate the sample. To prevent contamination, do not touch the inside of the bottle or lid.

* In W33, turbidity may be measured from a 1-quart sample if turbidity is NOT critical.

Arsenic and Uranium

125 mL Plastic
(4 oz.)

Collection Spot:
A kitchen faucet or a faucet used most often for drinking and cooking.

Protocol:
1. Turn on the cold water to its full capacity and let it run to waste for 2 to 3 minutes to flush the water out of the pipes.

2. Turn the faucet down to a pencil size stream of water and fill a 125 mL plastic sample bottle, being careful not to contaminate the sample. To prevent contamination, do not touch the inside of the bottle or lid.

W35-W40 (Microbiological Tests)

100 ml special plastic
bottle with essential dechlorinating agent (white powder) available at Feed and Environmental Water Laboratory and UGA county Extension offices.

Collection Spot:
A kitchen faucet or a faucet used most often for drinking.

3. Sanitize the faucet inside and out by dipping the faucet neck into undiluted chlorine bleach (do not use color-safe bleach).

4. Open tap fully and flush the faucet and pipes by running water for 3 minutes. If sampling from a faucet that mixes hot and cold water, run hot water for 3 minutes and turn it off, then run cold water for 3 minutes. Do not turn off the cold water, but reduce the flow to avoid splashing.

5. Uncap the sample bottle without touching the inside of the cap or bottle, fill the bottle above the 100 mL line (but not completely full) and recap tightly. Fill the bottle only once; do not rinse.

6. Submit the sample to the laboratory in person or ship it by overnight delivery option because the sample must be received by the laboratory within 24 hours of collection.

Common Water Quality Problems and Solutions

The most common water quality problems encountered
by private well owners in Georgia include
contamination by bacteria, abnormal taste, odor,
corrosiveness, hardness, and high levels of iron and
manganese. In some situations, well waters contain
some inorganic contaminants like nitrate, lead, copper,
arsenic and uranium at levels higher than EPA’s maximum
contaminant levels (MCL). Problems of organic
contaminants (for example, pesticides and petroleum
hydrocarbons) are not as common as the inorganic
contaminants.

In some water quality impairment situations (for
example, copper and lead dissolution from the plumbing
system), managing the sources of the problem is
more cost effective in the long run than installing and
maintaining a water treatment system. It is important
to know that one single type of treatment cannot address
all types of water quality problems. You should
purchase the appropriate type of treatment system that
will effectively solve your unique water quality issue.
The UGA water testing laboratory report contains an
unbiased interpretation and directions for treatment
options if an MCL is exceeded. Table 4 can be a useful
guide for identifying water quality problems with
your well, sources of contaminants causing the problems
and possible solutions.

Table 4. Common water quality problems, their sources and possible solutions1.

Symptom

Probable Cause

Possible Health
Effects

Standard/
Guideline

Suggested Remedy

Sudsy lather difficult to maintain in wash basin.

Greasy-grimy ring in bathtub.

White, scaly deposits in pipes or appliances or on glassware.

Hard water due to calcium and magnesium compounds
dissolved from rocks and minerals in the earth.

No health hazard

Generally contributes a
small amount to total calcium
and magnesium
dietary needs

Water appears clear when first drawn from tap, but if allowed to sit, fluffy brown or reddish-brown particles begin to form and settle to the bottom or water turns reddish-brown during cooking/ heating.

Reddish-brown stain in sinks, toilets and bathtubs.

Water has metallic taste.

Dissolved iron in ground water
from natural
sources gets
oxidized by air
and forms an
insoluble rusty
iron oxide.

Indicates more than 0.3 mg/L dissolved iron.

No known health
risk

Secondary MCL
Iron: 0.3 ppm

Shock chlorinate the entire well and plumbing systems (for a step-by-step shock chlorination procedure, see the footnote2 of this
Table). If problem returns, use:

Polyphosphate feeder for low levels of dissolved iron and manganese at combined concentrations up to 3 mg/l.

High capacity water softener recommended by the manufacturer for low to moderate levels of dissolved iron and manganese at combined concentration up to 5 mg/l.

Oxidizing filter (manganese greensand or zeolite or manganese oxide) for moderate levels of dissolved iron and manganese at combined concentrations up to 15 mg/l.

Aeration (pressure type) followed by mechanical filtration for high levels of dissolved iron and manganese at combined concentrations up to 25 mg/l.

Chemical oxidation with potassium permanganate or chlorination or ozonation followed by mechanical (sand) filtration for any level of dissolved or oxidized iron and manganese greater than 10 mg/l.

Reddish-brown or black slime
on walls of toilet flush tank.

Slimy materials suspended in clear water.

Reduced pumping capacity.

Iron-eating bacteria live in pipes and produce slimy material that hardens
into scale.

No known health risk

Disinfect the entire well and plumbing systems with shock chlorination; if condition persists, install a continuous chlorinator sand filter.

Not usually a health risk at concentrations present
in household water; however, hydrogen sulfide gas is flammable and poisonous if released at high concentration.

Secondary MCL
Sulfate: 250 ppm

Shock chlorination (see footnote2)
followed by discharge of large amount of water until chlorine and rotten egg odor dissipates. If the problem returns:

Install a continuous chlorination system followed by activated carbon filtration.

Install an iron and sulfur water conditioner.

Rotten-egg odor in hot water only.

Chemical reaction of magnesium
rod in hot water
heater in presence
of soft water.

No known health risk

Replace magnesium rod from heater with an acceptable alternative such as an aluminum rod.

Objectionable taste or odor other than hydrogen sulfide (e.g., a musty, earthy or woody smell).

Decaying organic matter.

Pollution from surface drainage.

Insufficient chlorine being used to disinfect water.

No known health risk in case of decaying organic matter.

Secondary
Standard

Odor: 3 TON (threshold odor number)

Install an activated carbon filter OR

Install an automatic chlorinator followed by an activated carbon filter.

Chlorine smell.

Excessive chlorination.

Chlorine in water is not poisonous
to humans or
animals.

High concentrations can cause imitation to tongue and make water taste odd.

Maximum residual
chlorine
allowed: 4.0 ppm

Install an activated carbon filter.

Detergent odor or foaming water.

Septic tank leakage into water supply.

Gastrointestinal illnesses (diarrhea,
vomiting, cramps).

Eliminate source and shock chlorinate well (see footnote2).

Methane gas odor.

Naturally decaying organic substances found in shallow wells near swamps.

Houses built above/near old landfills or aquifers overlying oil fields.

Gas is toxic to breathe and explosive.

If concentrations are above 28 mg/L, the U.S. Department of the Interior, Office of Surface Mining suggests that you take immediate action to reduce this concentration. Concentrations of 10 mg/L or less are considered
safe.

A well vent can remove methane from some wells. Contact a certified well contractor in your area to see if a well vent can be installed on your well. Aeration can also be used to remove methane.

Install a residential/commercial deaeration system and re-pump.

Gasoline or oil smell.

Fuel tank or underground storage tank leaking into water supply.

Discharge from factories or landfills.

Run-off from agriculture.

Varies depending on the contaminant, possibly:

Anemia

Increased risk of cancer

Liver and kidney problems

Primary Standard

Benzene <0.005ppm

Ethyl benzene <0.7 ppm

Toluene <1.0 ppm

Xylenes <10 ppm

GuidelineMTBE <0.20 ppm

Eliminate the source.

Install an activated carbon filtration system.

Sharp chemical odor in water (may also be odorless).

Leaching of pesticides into groundwater.

Anemia or other blood disorders.

Nervous system or reproductive disorders.

Increased risk of cancer or stomach, liver, kidney problems, etc.

EPA has specific standards for many pesticides.

Activated carbon filter OR

Reverse osmosis.

Turbid, cloudy or dirty water with suspended particles that settle out in water.

Suspended particles of silt,
clay and colloidal
matter.

Harmful contaminants
may be attached to soil/clay
particles.

Install:

An ew well screen AND

A cartridge-type sediment filter OR

An automatic sand filter.

Water unsafe or not potable due to coliform bacteria.

Contamination due to sewage, manure or surface runoff.

Health risk due to water-borne
disease-causing
microorganisms.

Primary MCL
Coliform bacteria: 0

Shock chlorinate the well and plumbing systems (see footnote2). If the condition persists, install:

Note that one particular type of treatment system cannot take care of all kinds of water quality problems and a
combination of methods may often be needed.

Depending on the nature and extent of contamination, most of the above treatment methods offer two major
types of water treatment devices:

Point of Entry (POE)

Point of Use (POU)

Point of Entry Water Treatment Systems

Point of Entry (POE), or whole house treatment systems, treat all water entering the home. They are more expensive
and are for treating a larger volume of water. They are useful when the water has problems that affect all areas of the home. The most common example
is a POE water softening ion exchange system that
removes calcium and magnesium ions (and some other
ions) from hard water. Even though hard water is not
unhealthy to drink, it can cause scale buildup in pipes
and on fixtures, interfere with the effectiveness of soap
and shorten the life of appliances like dish washers
and hot water heaters. Other POE water treatment systems
are also designed to remove iron and manganese,
adjust pH levels and add chlorine or other disinfectants.
The POE devices typically treat about 100-300
gallons per day, depending on family size.

Point of Use Water Treatment Systems

Point of Use (POU) systems treat water at the point
where it is used. These are the systems that are installed
at a specific location, frequently at the kitchen
sink, to treat only the water that is used for drinking,
cooking, etc. However, if other ports like the one on
a refrigerator and/or a bathroom sink are also used
for drinking, POU treatment systems should be installed
at those locations as well to ensure total safety
of drinking water. POU devices typically treat only
a few gallons of water per day, and generally only
water that will be directly consumed or used for cooking
needs to be treated. Such a system might be used
for contaminants like arsenic, cadmium, chromium,
fluoride, uranium, nitrate or radium, some organic
chemicals and sodium. Reverse osmosis, distillation
and activated carbon units are generally POU devices
because their main purpose is to provide few gallons
of clean water per day for drinking and cooking only.
It is cost prohibitive (and generally not necessary) to
install them as POE devices to treat all water entering
the home.

Some Common Water Treatment Techniques

Distillation

Distillation is a treatment method that normally removes
more than 99.9 percent of the dissolved minerals
in water. Tap water in a tank (often made of
stainless steel) is heated to boiling. Bacteria are killed
during boiling. The steam produced enters condensing
coils, where it is cooled and condensed back to water.
The distilled water goes into a storage container or is
piped to a special faucet. Storage containers can be
glass, metal or plastic. Dissolved minerals and other
dissolved and suspended substances are left behind
when the steam enters the condensing unit. Thus,
distilled water is considered relatively pure. Unevaporated
contaminants are left behind and periodically
flushed to the septic or sewer system. These units are
very effective in removing almost all common water
contaminants. The only exception is volatile organic
chemicals, which have a boiling point less than or
near that of water (for example, some pesticides and
volatile solvents) and are vaporized and carried into
the condensation chamber and condensed with the
distilled water.

Some distillation units have a volatile gas vent that
releases these vaporized contaminants to the atmosphere.
Filtering the distilled water through an activated
carbon filter is another way to remove most of
these organic chemicals. Except for small portable
units, most home distillation stills are connected to the
household plumbing. This maintains a constant supply
of feed water, which permits continuous operation
and production. A typical household unit will produce
between 4 and 12 gallons of treated water per day,
depending on the size of the heating element. The
known disadvantage of a distillation unit is the ongoing
cost of energy required for its operation.

Reverse Osmosis

Reverse osmosis (RO) is a membrane separation
process that employs a very thin membrane with tiny
pores to produce nearly pure water by separating out
most of the dissolved minerals and suspended particles.
Technically, this membrane is called a semipermeable
membrane, because it allows pure water to
pass through but retains any dissolved and suspended
constituents. More formally, it is the process of forcing
a solvent (pure water) from a region of high solute
concentration through a membrane to a region of low
solute concentration by applying pressure, a process
that is opposite of osmosis and hence called reverse
osmosis. Because only a portion of the water is forced
through the membrane and the remaining water containing
the unwanted materials is rejected, the system
produces a substantial amount of waste water (Figure
4). Several kinds of reverse osmosis membranes are
available. Each type has advantages and disadvantages.
A membrane should be selected that will best
remove the contaminants of interest. Sample and analyze
the water before and after the treatment to determine
the efficiency of the system.

Home RO units only treat about 5 to 10 percent of the
flow through the unit and waste the remainder. Thus,
if you are on a septic system, for every 1 gallon of
treated water you may be discharging 9 to 19 gallons
of water into your septic system. For this reason, RO
systems are not feasible for treating all the water for
a home. They are usually installed at the kitchen sink
and connected to the household plumbing. A typical
unit will treat between 5 and 20 gallons of water per
day. Operation and maintenance costs of an RO unit
are considerable – you have to replace the filtering
membrane unit on a regular basis as recommended by
the manufacturer.

Many RO units can provide up to 95 percent removal
of a variety of inorganic and some organic chemicals.
However, it is not effective against dissolved gases
(e.g., hydrogen-sulfide, radon and trihalomethanes)
or most volatile and semi-volatile organic contaminants,
including some pesticides and solvents. A list
of contaminants that could be treated effectively by
RO membrane filters is presented in Table 5. This
table is not an exhaustive list of contaminants that RO
may remove, but rather lists those for which RO can
be a practical method for treating household drinking
water.

* Many RO systems also include an activated carbon filter, which
will allow for the reduction of additional contaminants that
reverse osmosis units alone are not effective for (see section on
Activated Carbon Filters).

† Although the RO membrane is capable of rejecting virtually
all microorganisms, it can develop pinholes or tears that allow
bacteria or other microorganisms to pass into the treated water.
RO units alone are not recommended for treatment of bacteria
and other microscopic organisms.

Activated Carbon Filters

Activated carbon (AC), also called activated charcoal,
is usually derived from charcoal. It is a form of carbon
that has been processed (activated) to make it extremely
porous and thus have a very large surface area
available for adsorption or chemical reactions. Most
AC filters are made from raw materials such as nutshells,
wood, coal, etc. Typically, 1 gram of AC may
have a surface area of 1000 square-meter or more.
Activated carbon is an adsorption medium, meaning
that substances become bonded to the carbon and are
tightly held there.

Filters are available in cartridge units for point-of-use
treatment and in tank type units with granular activated
carbon for point-of-entry treatment. When the
absorption capacity of the activated carbon is used up,
the media should be replaced for the filter to remain
effective. A filter with a spent cartridge may be worse
than no filter at all. Some recent studies show that if
you don’t replace your filter as recommended, bacteria
can grow within the medium and become a source of
drinking water contamination.

Solutions to Some Specific Water Quality Problems

Bacterial Contamination

Water that is found to contain coliform bacteria is not
safe for human consumption because the presence of
coliform bacteria in well water indicates a possible
source of entry for disease-causing organisms into the
well.

If possible, locate the source of contamination and
eliminate the problem at its source. Several origins of
bacterial contamination are possible, the most common
being surface water entering the well. This can
usually be prevented by proper well construction and
several wellhead protection measures (Figure 6) such
as:

Extending the well casing above ground level

Sealing around the well casing with tight clay at
least 10 feet deep from the surface (technically
called grouting)

Further sealing around the well casing with a
concrete slab

Sealing the top of the casing with a sanitary well
cap

Diverting all surface waters away from the well
area

For further information about wellhead protection,
refer to University of Georgia Cooperative Extension
Circular 858-1, Protecting your Well and Well Head,
available at your local Extension office and online at
http://www.caes.uga.edu/publications.

Figure 6: Domestic well diagram with adequate well-head protection measures (adapted from
Arizona Department of Water Resources Well Owners Guide).

Other sources of contamination are septic tanks or
sewage lines located too close to the well. Run-off or
leaching from livestock operations can also contaminate
wells. A recent study showed that the occurrence
of contamination of well waters by coliform bacteria
in Georgia is substantial, regardless of well types and
age (Figure 7). That means much is left to be done to
ascertain proper well construction, wellhead protection,
and water testing and treatment to minimize the
risk of water-borne diseases.

Figure 7: Rate of coliform contamination in well waters of Georgia for various well ages and well
types (Source: Saha et al., 2011).

If your water tests positive for coliform, you should
take immediate steps to eliminate the source of contamination
(if you can locate the source) and shock
chlorinate the well and distribution system to get rid
of the remaining bacteria. To shock chlorinate the well
and distribution system, introduce a concentrated chlorine
solution directly into the well and mix, then circulate
the chlorinated water throughout the water system
and allow it to stand overnight. Finally, flush the lines
until the chlorine odor is no longer evident. For further
details about shock chlorination procedures, refer to
University of Georgia Cooperative Extension Circular
858-4, Disinfecting Your Well Water: Shock Chlorination,
available at your local Extension office and
online at: http://www.caes.uga.edu/publications. Shock
chlorination is required after construction, pump
installation and after every major service operation.
Anytime a pump is removed from a well and replaced,
there is a chance of bacterial contamination.

If you cannot eliminate the source of contamination
and/or experience recurrent contamination even
after repeated shock chlorination, consider alternative
sources of water. If this option is not feasible, you may
have to resort to continuous disinfection of the water
supply. Various water disinfection methods include
chlorination, ultraviolet light and ozonation.

Chlorination

The most common, oldest and relatively inexpensive
method of disinfecting water is chlorination, which
is basically addition of bleach (chlorine solution) to
the water. Chlorinators inject chlorine solutions into
water systems at a controlled rate to ensure the desired
chlorine concentration in the treated water. They are
readily available and easily installed. Chlorine is a
very effective disinfectant and oxidizing agent. With
sufficient concentrations and adequate contact time, it
kills pathogens, including bacteria and certain viruses,
but does not kill Cryptosporidium, Giardia and some
other microscopic organisms. It also readily combines
with other components dissolved in water including
iron, manganese, hydrogen sulfide, organic matter,
ammonia, and organic color such as that from decaying
peat moss. Thus, it also removes some bad odors,
tastes and colors. However, chlorine can react with
dissolved organic material and produce some toxic
chemicals like trichloromethane (chloroform) that may
be linked to human health hazards.

The part of the added chlorine used for initial disinfection
and reaction with other dissolved components of
water is called “chlorine demand of water.” The added
chlorine that is left after being used up for satisfying
the chlorine demand of water is called “free chlorine
residual.” By maintaining a certain level of free chlorine
residual you ensure a continued disinfection of the
treated water until it is used. According to CDC (Centers
for Disease Control and prevention), treated water
should contain a free chlorine residual of at least 0.5
ppm to be safe (microbiologically) for drinking and
no more than 2.0 mg/L to be free from any unpleasant
taste or chlorine odor.

The time required for chlorine to effectively destroy
bacteria is known as the contact time. A contact time
of at least five minutes is recommended, provided a
free chlorine residual of 0.5 to 1.0 ppm is maintained.
In order to provide adequate contact time, install an
intermediate storage tank with a theoretical water
detention time of 10 to 15 minutes. For instance, if the
pump capacity is 10 gallons per minute then the storage
tank should hold at least 100 gallons to ensure 10
minutes of desired contact time. The pressure tank is
usually not adequate for providing extra contact time
because when water is being pumped and drawn at
the same time, the fresh water may by-pass the water
already in the pressure tank.

Household laundry bleach (sodium hypochlorite,
NaOCl) containing 5.25 percent available chlorine can
be used as a source of chlorine. Calcium hypochlorite
Ca(OCl2), in powder or tablet form, may also be used
as a concentrated source of chlorine to prepare a stock
solution. Mix according to label directions to obtain
the proper concentration of chlorine. After mixing,
inject only the clear solution. Any sedimentation in the
bottom of the container should be discarded. A fresh
solution should be prepared at least once per week.
Follow the instructions provided by the manufacturer
functioning
and maintenance of the chlorination unit.

Use a free chlorine test kit to periodically check the
free chlorine residual of the treated water. These test
kits are usually available from water treatment system
suppliers. Information about borrowing and testing
chlorine in your water using a test kit are available at
your local Extension office and online at http://aesl.
ces.uga.edu/Water/ChlorineTest.pdf.

Ultraviolet Light

Ultraviolet (UV) light has been used to disinfect public
water supplies for more than 75 years, but home
UV systems have become available only recently. This
type of water treatment uses a low pressure mercury
arc lamp that emits UV light to kill pathogens in the
water. The equipment consists of ultraviolet lights surrounded
by tubes through which the water must pass.
Bacteria exposed to the UV light are destroyed or
inactivated. The principal advantage to UV treatment
over chlorination is that it disinfects water without using
any chemicals, and thus does not impart any taste
or odor to the water. Furthermore, some water-borne
microorganisms are chlorine-resistant, so chlorination
may not be adequate to rid your tap water of dangerous
levels of some pathogens.

Although UV treatment is effective, disinfection only
occurs within the unit. No disinfection occurs beyond
the treatment unit to kill microorganisms that survived
or were introduced in the system after UV treatment.
Unlike chlorination, where easily measured “free
chlorine residual” can be used as an indicator of continued
bacteria-free water, a UV unit requires expensive
microbiological tests from time-to-time to verify
adequate performance.

UV light kills bacteria, viruses and some cysts. It does
not kill either Giardia lamblia cysts or Cryptosporidium
parvum oocysts, both of which must be removed
by microfiltration or distillation. UV is not recommended
if the untreated water has a coliform content
exceeding 1,000 total coliforms or 100 fecal coliforms
per 100 milliliters.

The bacteria must be exposed to the UV light for a
certain length of time to ensure disinfection. Color,
turbidity, scale build-up due to hard water, and organic
impurities in water interfere with the transmission of
the ultraviolet energy and may reduce the disinfection
efficiency to unsafe levels. Ongoing costs of energy
and UV-lamp replacement should be considered before
installing a UV disinfection system.

Emergency Measures

If you suspect bacterial contamination of a water supply,
take emergency measures to make sure the water
is safe for consumption until permanent solutions can
be employed. If alternate water sources are not available,
boil or shock chlorinate the water before drinking.

Boiling the water vigorously for at least two minutes
will destroy harmful organisms. Once the water is
cooled, it must be protected from recontamination.
The boiled water will have a “flat” taste that you can
eliminate by aeration.

In order to shock chlorinate drinking water, add 1/8
teaspoon (or eight drops) of regular, unscented, liquid
household bleach to 1 gallon of water, stir it well and
let it stand for 30 minutes. Although the water may
have an objectionable chlorine taste, it will be microbiologically
safe to drink. You can reduce the chlorine
taste by heating the water or allowing it to stand for a
longer period of time.

Hard Water

Water hardness is due to the presence of certain dissolved
minerals, primarily calcium and magnesium.
Hard water can cause scale build-up in hot water
pipes, water heaters and plumbing fixtures, thereby
increasing the costs of heating water and reducing
the life of the appliance and plumbing system. Hard
water minerals also interfere with the cleaning action
of soaps and detergents, forming film on skin,
clothing and fixtures. However, there is no known
health hazard due to drinking hard water. For further
information, refer to University of Georgia Cooperative
Extension Circular 858-9, Your Household Water
Quality: Corrosive or Scaling Water, available at your
local Extension office and online at: http://www.caes.
uga.edu/publications.

Water hardness is reported in one of two ways, either
as milligrams per liter (parts per million) as calcium
carbonate or as grains per gallon. The most common
method used on water test reports is grains per gallon.
The degree of water hardness is classified as follows
(Table 6):

Table 6. Classes of water hardness.

Water Hardness

Grains per Gallon

Parts per
Million (ppm)

Soft
Slightly Hard
Moderately Hard
Hard
Very Hard

0 to 0.99
0.99 to 3.5
3.5 to 7
7 to 10.5
more than 10.5

0 to 17
17 to 60
60 to 120
120 to 180
more than 180

Water with hardness exceeding about 7 grains per
gallon or approximately 120 mg/L (parts per million)
may interfere with the cleaning capacity of soaps and
detergents, thereby affecting laundering, washing
dishes, bathing and personal grooming.

The most common method of removing hardness
for an individual water system is ion-exchange, also
called water softening. A household water softener
contains a “mineral tank” containing a column of
material called “cation exchange resin beads.” As
the hard water passes through the mineral tank, the
column of resin beads releases sodium into the water
and adsorbs or removes calcium and magnesium
from the water. As the exchange continues, the column becomes saturated with calcium and magnesium.
The column is then regenerated by back-washing the
resin with a concentrated solution of rock salt (sodium
chloride) prepared in another tank called the “brine
tank.” The excess salt, calcium and magnesium solution
is washed (rinsed) out of the resin, and the resin
is again ready to exchange sodium for calcium and
magnesium.

Water softeners are available with automatic, semiautomatic
or manual regeneration. Fully automatic
units regenerate on a predetermined schedule (usually
controlled by a clock) and return to service automatically.
Semiautomatic units are started manually, but
otherwise operate automatically. With manual units,
all steps (backwashing, brining and rinsing) are performed
manually.

Turbid water, or water with iron or bacterial slimes,
can clog a water softener. If these impurities pose a
problem, filter them out before the water enters the
softener or clean the softener manually periodically.

Water softeners are sized according to the water hardness
and the daily water requirements of the household.
Usually, softened water is supplied only to the
bathtub, lavatories, kitchen sink and laundry. Water
for the toilet and for the lawn, garden and other nonhousehold
uses is usually not softened. This reduces
the load on the unit and thus the frequency of recharging.
As a rule the softener should be large enough to
last at least three days between regenerations.

In softening water with an ion-exchange softener,
sodium is added to the water. For this reason, people
on a restricted sodium diet (for example, individuals
with high blood pressure) should consult with their
health professionals before drinking softened water
long-term.

Nitrate

Nitrate (NO3) is a primary form of nitrogen (N) for
plant growth. Nitrate fertilizers are used extensively in
agriculture. If properly managed, the use of nitrogen
for agriculture does not pose a particular health problem
by contaminating drinking water supplies. However,
when more nitrogen is added to the soil than the
plants can use, excess nitrate can leach into groundwater
supplies. For further information, refer to University
of Georgia Cooperative Extension Circular 858-5,
Your Household Water Quality: Nitrate in Your Water,
available at your local Extension office and online at:
http://www.caes.uga.edu/publications.

Human infants, infant monogastrics (such as baby pigs
and chickens) and ruminant animals (such as cows
and sheep) have bacteria in their digestive systems
that convert nitrate to nitrite, a very toxic substance.
When nitrites are absorbed into the blood, they make
the hemoglobin (red blood pigment carrying oxygen)
incapable of releasing the oxygen and mild symptoms
of asphyxiation (a condition of deficient oxygen supply
to the body) appear. Infants under six months of
age are most affected by excess nitrates in the water.
They may eventually develop a condition called methemoglobinemia
(blue baby syndrome), which causes
a bluish color around the lips, spreads to the fingers,
toes and face, and eventually covers the entire body.

Nitrate test results are usually expressed as nitratenitrogen
(NO3-N); however, some laboratories may
report the amount as nitrate (NO3). Nitrate-nitrogen
is just the nitrogen portion of the nitrate ion: Nitrate
(mg/l) = Nitrate-Nitrogen (mg/l) x 4.427. Because
of the difference between the number expressed as
nitrate-nitrogen or as nitrate, it is essential to use the
correct scale to interpret your water test report. If your
test report is unclear whether the number reported is
nitrate or nitrate-nitrogen, check with the laboratory.

A water quality standard of 10 milligrams per liter
nitrate-nitrogen (mg/l NO3-N) has been set for human
consumption and 100 mg/l NO3-N for livestock.

If you find your water supply is contaminated with
nitrate, take steps to locate the source of contamination.
Nitrates can enter the ground water through
fertilizer application, feedlot runoff or septic systems.
Make sure the well is properly cased, the wellhead is
adequately protected and that surface water is diverted
away from the well (see the section on coliform bacteria
in this publication). Also, the well should be at
least 50 feet away from a septic tank and at least 100
feet away from a septic tank absorption field because
both are potential sources of contamination. A test
for bacteria is suggested when well water shows high
levels of nitrate, and vice versa. Septic system leakage
is the most likely source of nitrate contamination in
your well.

Once a water supply becomes contaminated with
nitrate, it is very difficult and costly to treat. It may be
practical to treat only household drinking water, but it
would be very costly to treat the large volumes of water
consumed by livestock or used for other household
uses. The possible methods of reducing or removing
nitrates from water are: demineralization and anion
exchange. Demineralization removes nitrates and
all other minerals from the water and can be accomplished
in two ways: distillation and reverse osmosis
(described earlier in this publication).

The anion exchange system operates on the same principle
as a water softener. The water passes through a
column of resin beads in which nitrate and sulfate ions
are exchanged for chloride ions. The resin is recharged
by backwashing with a brine solution (sodium chloride)
just as with a water softener. Since this process
also removes sulfates, any sulfate in the water supply
may interfere with nitrate removal. The resin may also
make the water corrosive, requiring the water to go
through a neutralizing system after going through the
anion-exchange unit.

Acidity

In ground water, the cause of acidity is usually free
carbon dioxide in the water. The gas may come from
decaying organic matter or it may be carried down
from the air by rainwater. Some sand aquifers have
naturally occurring acidic water because they do not
contain minerals that buffer the pH. In some cases,
especially in mining areas, water may contain free
mineral acid—hydrochloric, sulfuric or nitric.

Acid water causes problems by corroding the metal
parts of water systems. The first symptoms of acid water
usually appear in the form of stains in toilets, sinks
and other fixtures. The color of the stains will depend
on the kind of metal being attacked—green or blue
stains from copper and red or brown stains from iron.
If the corrosion is allowed to continue, the metal will
slowly be eaten away, and the system will ultimately
fail. Lead in water is also usually the result of water
acidity, which dissolves lead from soil, rock or from
the plumbing system. Lead piping and lead solders
in copper pipes are found in many houses built prior
to 1986. Lead is a primary contaminant in drinking
water that causes some serious health consequences if
water containing lead above the MCL is consumed for
a considerable period of time. Concentration of lead
in water exceeding the MCL, however, does not cause
any abnormal color, odor or taste.

The acidity or alkalinity of water is measured on a
scale known as pH. The pH can vary from 0 to 14,
with a pH of 7 being neutral. If the pH is below 7, the
water is acidic; above 7, it is alkaline. Ideally, the pH
of domestic water should be between 6.5 and 8.5 pH.
Values below 6.5 usually indicate corrosive water; if
the pH is above 8.5, the water is usually hard.

The most obvious solution for treatment of acid water
is to neutralize the acidity. One of the simplest ways to
do this is to install a neutralizing filter, which contains
a bed of material such as calcium carbonate or magnesium
oxide. As the water passes through the filter,
the acid is neutralized and a small amount of the bed
is dissolved. Neutralizing filters must be backwashed
periodically because they also serve as mechanical
filters to remove solid particles from the water. Also,
from time to time the bed needs to be replenished to
replace material that was dissolved. Acidic water can
also be neutralized by injecting a solution of soda ash
(sodium carbonate) in the water supply with a chemical
feed pump.

Where acidity is the only problem, the neutralizing filters
are usually the best approach. However, if the water
contains high levels of iron or manganese or if the
water requires disinfection, the chemical feed pump is
often used, since chlorine (for disinfecting) and soda
ash may be mixed in a single solution and fed into the
water system with the same pump unit.

Turbidity

The presence of suspended materials such as clay, silt,
finely divided organic material, plankton, etc. absorb
or reflect light and result in cloudy or muddy water.
Turbidity is measured based on light transmission
through water; light transmission is lower through
turbid waters than clean waters. Even though surface
waters are frequently turbid, turbidity problems with
well waters is also found, especially when the well
screen is not sized correctly or the water table drops
and the water cascades into the well. If the well is
drilled through fractured rock you can have turbidity
problems – and the grit can damage your pump.

The major problem with turbidity is aesthetics, but
in some cases suspended matter can carry pathogens
with it. Large amounts of organic matter can also
produce stains on sinks, fixtures and laundry. Organic
matter in water may also produce colors, unpleasant
tastes and odors. These tastes and odors will affect not
only drinking water, but also the foods and beverages
prepared with the water. If turbidity is greater than 5
turbidity units (NTU – Nephlometric Turbidity Units),
be aware of possible bacterial contamination.

Mechanical filtration is required for the removal of
turbidity. Two different types of filters may be used,
either individually or in combination. One is the sand
filter and the other is the cartridge filter.

The sand filter consists of a tank containing an 18- to
24-inch-deep bed of fine sand on top of a layer of
fine gravel. The water passes through the sand bed
to filter out suspended particles. The filter must be
backwashed periodically to clean the beds and to flush
away accumulated sediment. The sand filter is effective
in removing all but extremely fine particles.

The cartridge filter is usually much smaller than the
sand filter and is often used in the water line to a
specific tap. These filters use media that is formed or
molded into more or less rigid cartridges. Most cartridges
are designed to be replaced when they become
clogged with accumulated solids. The cartridge filter
is very effective in removing extremely fine particles.
It is always better to remove the exhausted filter than
leave it in and not replace it when needed because
bacteria can grow in the filter material.

A sand filter is best for removing heavy loads of suspended
particles, while the cartridge filter may be used
as secondary filtration at the point of use to remove
very fine particles not removed by the sand filter. If the
turbidity is relatively low, the cartridge filter may be
all that is needed.

Often, some new wells may initially yield turbid water
due to high levels of suspended solids added during
the drilling process. These solids can usually be
removed by an initial period of continuous pumping,
called well “development.” Cartridge filters can be
used initially and after the well clears up, although the
cartridge should be removed to bypass the system.

Iron and Manganese

Iron and manganese are common problems encountered
with private water systems in Georgia. Iron gives
water a bitter, metallic taste, stains clothes and fixtures
and promotes the growth of iron bacteria in plumbing.
Manganese causes similar problems and can be removed
by the same procedures used for iron. The secondary
MCLs are 0.3 ppm for iron and 0.05 ppm for
manganese. For further information, refer to University
of Georgia Cooperative Extension Circular 858-11,
Your Household Water Quality: Iron and Manganese,
available at your local Extension office and online at:
http://www.caes.uga.edu/publications.

Iron can be present in two forms: oxidized or reduced.
The reduced form of iron is present in an oxygen-free
environment, such as ground water. This form of iron
is water soluble and colorless. When reduced iron is
oxidized, it forms a red or yellow insoluble precipitate.
It is the oxidized form of iron that stains plumbing fixtures
and clothing. Iron can be oxidized by exposure to
air or oxidizing agents such as chlorine, permanganate
and manganese green sand used as filter media in the
water treatment industry.

Iron bacteria can be a problem with iron concentrations
as low as 0.1 ppm. Iron bacteria form slime
growths or gelatinous masses in plumbing and use
the iron in the water as an energy source. They do
not cause disease but can be a real nuisance. Heavy
growths can completely plug pipes, but usually break
loose during periods of high water flow to produce
slugs of dirty iron- or manganese-laden water with
obnoxious tastes and odors. A reddish-brown slimy
growth in a toilet flush tank is a good indication of
the presence of iron bacteria in a water system. Iron
bacteria can be removed by shock chlorinating the
well and whole plumbing system as described earlier.
If the problem persists, continuous chlorination may
be necessary.

Several methods are available for removing iron and
manganese from water. The best method for you will
depend on the concentration and whether or not the
iron or manganese is in the oxidized or reduced form.

High-capacity Water Softeners for Iron and Manganese Removal

In addition to removing calcium and magnesium in
exchange for sodium, water softeners will remove the
reduced forms of iron and manganese. Water softeners
are effective up to 5.0 ppm of combined iron and
manganese. It is important to note that water softeners
are only effective on reduced iron and manganese
(which are soluble forms); oxidized forms (solid
particles or precipitate) will foul the unit. If oxidized
forms are present, they should be removed by a sand
filter before the water reaches the softener.

Oxidizing Filter

Oxidizing filters are recommended when:

Iron or manganese concentration is too high for a
water softener

Much of the iron is oxidized

Iron removal without softening is desired

The media in these filters is capable of oxidizing iron
or manganese to the insoluble state and removing
the precipitated matter all in the same tank. This is a
point-of-entry treatment method. The two major types
of filter media commonly used are manganese greensand
and manufactured zeolite coated with manganese
oxide.

These filters must be backwashed periodically to flush
the accumulated deposits. When the oxidizing capacity
of the filter medium declines substantially, the
medium has to be regenerated with a weak potassium
permanganate solution to restore the oxidizing capacity.
These filters are effective with combined iron and
manganese concentrations up to 15 ppm. The pH of
the water should be above 7.0 for the filter to be most
effective.

Chemical Oxidation Followed by Mechanical Filtration

Chemical oxidation followed by mechanical filtration
is also a point-of-entry treatment method that oxidizes
dissolved iron and manganese into solid particles that
are subsequently filtered out of the water. This is the
accepted method of iron and manganese removal
when their combined concentrations are greater than
10 ppm. This treatment is particularly valuable when
iron is combined with organic matter or when iron
bacteria are present. This method destroys iron bacteria,
which would foul a water softener or oxidizing
filter.

With this type of treatment system, an oxidizing
chemical is added into the water by a small feed pump
that operates when the well pump operates. Addition
of chemical is typically done just before the water
enters a storage tank. Generally, the oxidation process
requires at least 20 minutes of retention time in
the storage tank. Sometimes the chemical is added to
the well to control the iron bacteria. Dissolved iron,
manganese and hydrogen sulfide are oxidized, forming
solid particles. Oxidizing chemicals that can be used
are:

Chlorine

Potassium permanganate

Hydrogen peroxide

In addition to its oxidizing effect, a special advantage
of using chlorine is its bactericidal effect. Iron
and manganese bacteria, along with other bacteria,
are destroyed. However, iron oxidation by chlorine is
most effective if water pH is 6.5 to 7.5. Consequently,
chlorination is not recommended for treatment of
high levels of manganese because a pH level of 9.5
or greater is required for complete manganese oxidation.
In contrast, potassium permanganate can oxidize
manganese at pH levels of 7.5 or higher and is also an
effective method of oxidizing organic iron.
The solid particles formed in the oxidation step can be
subsequently removed through a mechanical filter (a
sand filter, for example).

Sulfur Water

A strong rotten egg taste or odor usually indicates the
presence of hydrogen sulfide in the water. Water containing
this gas is commonly known as “sulfur” water.
Not only does it have a bad taste and odor, it can also
corrode iron and other metals and cause stains in
plumbing fixtures. Treatment is usually needed if there
is more than 1.0 ppm of sulfur in the water.

When only small amounts of hydrogen sulfide are
involved (6 ppm or less), an iron-removal filter will
remove the sulfur satisfactorily. If concentrations are
higher (greater than 6 ppm), the hydrogen sulfide can
be removed by chlorination followed by filtration
through a sand filter. The chlorine will oxidize the sulfur,
changing it to an insoluble form, and the filter will
remove the suspended particles. The chlorine will also
kill sulfur bacteria if they are present.

If your water system has not been used for a while, if
the well has not been pumped or your storage tank has
not been flushed, stagnant water can generate a rotten
egg odor. Flushing your system can reduce the odor.

Arsenic and Uranium

Arsenic (As) is a trace element of concern in some
well waters in Georgia. It naturally occurs in some
aquifer sediments. Test results from UGA’s water
laboratory and Georgia’s Environmental Protection
Division revealed that some well waters had arsenic
concentrations above the MCL of 10 ppb, which the
EPA considers unsafe for drinking. These samples
were widely distributed geographically in Camden,
Irwin, Tift, Bibb and Lowndes counties. For further
information about arsenic occurrence and health
concerns of arsenic exposure, refer to University of
Georgia Cooperative Extension Circular 858-12, Your
Household Water Quality: Arsenic in Your Water,
available at your local Extension office and online at
http://www.caes.uga.edu/publications.

There are typically two forms of arsenic in water:
“arsenic-III” and “arsenic-V,” but arsenic-III often
predominates in the groundwater. Arsenic-III is much
more toxic to humans and is relatively difficult to
remove compared to arsenic-V. Therefore, any water
filtration should remove both forms of arsenic. The
preferred water treatment is to remove arsenic from all
water entering the house using granular ferric oxide,
titanium or hybrid adsorption media that contains
iron-impregnated resin. These systems effectively
remove both “arsenic-III” and “arsenic-V.” A smaller
and lower-cost filtering system at the point-of-use can
be an alternate choice, which would provide 2 quarts
of treated water per minute, enough for drinking and
cooking in an average household. For further information
about arsenic removal, refer to the University of
Georgia publication Removal of Arsenic from Household
Water, available at your local Extension office
and online at: http://www.caes.uga.edu/publications.

Uranium (U) is another trace element that has been
found in some well waters exceeding the EPA MCL
of 30 ppb. Uranium is naturally occurring in certain
kinds of aquifer bedrock. In Georgia, waters that could
be high in uranium are located primarily in the Piedmont
and Blue-Ridge regions located in the northern
part of the state (above the “Fall Line”) and supplied
by wells deeper than 100 feet in granitic bedrock.
Levels of uranium above 30 ppb have not been found
in shallow wells or surface water. An affordable home
water-treatment option is a “point-of-use” reverse
osmosis (RO) system that produces 5 to 20 gallons of
drinkable water per day and removes 90 to 99 percent
of uranium. For further information about uranium in
drinking water and its treatment, refer to University of
Georgia Cooperative Extension Circular 858-14, Your
Household Water Quality: Uranium in Your Water,
available at your local Extension office and online at:
http://www.caes.uga.edu/publications.

Independent Validation and Certification of Water Treatment Equipment

There are numerous water treatment systems on the
market that claim to effectively handle various practical
water quality issues. Well owners may get confused
by competing, often contradictory, statements
and have difficulty determining which claims are
accurate. The importance of validating the accuracy of
advertising literature of the product, followed by certification
by an independent third party, is paramount.
If a treatment system is certified by a reputable third
party, well owners can be assured that the product will
perform as specified. In the water treatment industry,
NSF International (http://www.nsf.org) and the Water
Quality Association (WQA, http://www.wqa.org) are
two recognized organizations involved in independent
validation and certification of various products.

National Sanitation Foundation (NSF) International
is a nonprofit organization dedicated to
solving health and environmental problems. They
provide product certification and listing services
that show the results of third-party evaluations,
testing and inspection programs performed on
water treatment units. Their certification of a
treatment system means that it not only performs
as claimed, but also that the advertisements associated
with the product in the market are accurate
and true. Products are tested on an ongoing
basis to make certain that companies continue
to produce products that perform as advertised.
Thus, the NSF is an unbiased source of consumer
protection against fraudulent dealers. However,
an NSF seal only means that the device has been
tested according to NSF protocols and passed.
This does not always mean that the product will
continue to perform for extended periods of time.

WQA is a self-governing body of manufacturers
and distributors of water treatment products. The
association provides educational materials to the
consumer, a product testing service for the industry
and promotes the use of treatment equipment.
The WQA has developed a “Gold Seal” program
for member products that have been tested and
approved by the association. The WQA tests
prototype water treatment equipment and awards
the “Gold Seal” only to those systems that have
met or exceeded industry standards for contaminant
reduction performance, structural integrity
and materials safety. WQA attempts to police the
industry to eliminate firms that sell products that
do not perform as per advertising claims.

The NSF program established performance standards
that must be met for endorsement and certification.
The WQA program uses the same NSF standards and
provides equivalent American National Standards
Institute (ANSI) accredited product certifications.
Though these certifications and validations should
not be the only criteria for choosing a water treatment
system, they are helpful to ensure effectiveness of the
system. There are currently seven ANSI/NSF standards
relating to water filtration and treatment devices,
each one designed for a specific type of product.

STANDARD 42: Drinking Water Treatment
Devices - Aesthetic Effects

STANDARD 44: Cation Exchange Water
Softeners

STANDARD 53: Drinking Water Treatment
Devices - Health Effects

STANDARD 55: Ultraviolet Microbiological
Water Treatment Systems

STANDARD 58: Reverse Osmosis Drinking
Water Treatment Systems

STANDARD 62: Drinking Water Distillation
Systems

NSF/ANSI 177: Shower Filtration Systems -
Aesthetic Effects

You should know exactly what a specific certification
standard stands for if the certification is to be useful.
The NSF site has online comparisons of many of the
products they certify. Check out the NSF site, and use
it as one of your guides in choosing a reliable product
by selecting “Drinking Water Treatment Units” and
then entering one or more of the following pieces of
information:

A company name you are interested in investigating
(if any)

Brand name/Trade name/Model you are interested
in investigating (if any)

The product standard (42, 44, 53, etc.)

Product type (countertop filter, under counter
filter, etc.)

Facility location (e.g., Georgia)

Other organizations like the Better Business Bureau,
County Extension Offices, and Consumer Reports can
provide additional unbiased information to prospective
treatment equipment buyers. Because these organizations
often deal directly with consumers, they know
the success and failure rates of various devices and
may provide buyers with information like company
reputation, warranties, and facts on water treatment. A
wise consumer should seek out one or more third party
opinions before selecting a company or device
(Table 7).

Table 7. Sources of information and product evaluators for
drinking water treatment equipment.

Cautionary Note: In researching water purification
devices, it is often found that many companies state on
their literature some vague claims like, “Tested to NSF
standards” or “Tested and Certified in Accordance
with NSF/ANSI Standards 42 and 53” (with the NSF
logo displayed). Such statements do not ascertain that
the product is certified by NSF because the answers to
the following pertinent questions are unknown:

Tested by which organization?

Tested how often?

Who backs up that claim and provides certification?

Water treatment systems that carry such vague statements
in their advertisement literature are often not
found in the list of certified products available online
at the NSF website.

Questions to Ask When Purchasing Water Treatment Equipment

With the recent expansion of the home water treatment
industry, new products are constantly being introduced
with claims of solving a variety of water quality
problems. Consumers often make costly decisions
about water treatment equipment without being well
informed. In many cases, people simply do not know
what questions to ask to ensure a worthy investment.
The following are some important questions that you
should ask water treatment professionals to determine
the treatment system that you need. The extent
to which the manufacturer or distributor is willing to
provide answers can assist the consumer in making an
informed choice.

1. What exactly does the analysis of the water by
the treatment professional show? Are health hazards
indicated? Should more testing be done?

Many water treatment companies include in their
services free in-home testing of the water. Not all
contaminants can be evaluated this way; for example,
arsenic, uranium or organics, which have been associated
with serious health problems, must be analyzed in
a laboratory with sophisticated equipment. The consumer
must question the validity of analyses claiming
to determine more than some basic water quality
constituents such as hardness, pH, iron and sulfur. You
should have a qualified individual examine your test
results before making any purchasing decisions based
on free water tests. The county health department,
county Extension office, or water testing laboratory
manager can help you evaluate water test results.

2. How long has the company been in business, and
is there a list of referrals the consumer can contact?

Make sure the company is reputable and established.
Ask the company for referrals and contact the referrals
to find out customer satisfaction. Talk to your local
health department to see if they have had any experience,
good or bad, with the company.

3. Is the product tested and certified by the National
Sanitation Foundation (NSF) or the Water
Quality Association (WQA) for performance?

A product tested by an independent testing agency
such as NSF or WQA will have a seal as shown below,
indicating that it meets industry standards for water
treatment performance.

Do not buy a device that does not have a seal indicating
it meets industry standards.

4. Was the product tested for the specific contaminant
in question and over the advertised life of the
treatment device under household conditions (tap
water, actual flow rates and pressures)?

If no test results are available, consider purchasing a
different brand. You should examine test results of the
device carefully to determine if the manufacturer’s
claims are realistic. For example, some reverse osmosis
units are often claimed to be effective in removing
arsenic and carry an NSF certified seal. That certification
is only for Arsenic-V, but not for Arsenic-III.

When both Arsenic-V and Arsenic-III are found in the
well waters in Georgia, the reverse osmosis unit will
not be a practical solution to the arsenic contamination.

5. Is a second opinion on treatment procedures and
equipment necessary?

Consider getting a second opinion on recommended
water treatment equipment. Check with at least one
additional dealer to see what treatment procedure and
equipment is recommended and ask questions. Compare
at least two brands and consult other references.

6. Does the specific water problem requirewholehouse
treatment (point of entry) or a single-tap
device (point of use)?

The water treatment device selected depends on the
contamination problem. For example, disinfection by
chlorination or an ultraviolet system is generally done
by a POE system, where all water used in the house
should be treated. For most contaminants, treatment of
only drinking and cooking water will provide safety at
a reduced cost.

7. Will the manufacturer include follow-up water
testing in the purchase price to ensure the equipment
is working properly after a month or two?

Testing the water a month or two after the equipment
is installed will assure the homeowner that the unit is
accomplishing the intended treatment. You should ask
for a written guarantee that the device will correct the
specific problem, as documented by water testing a
month or two after installation.

8. Will the device produce enough treated water to
meet daily household requirements?

The maximum flow rate should be adequate for peak
home use. You may also need to check whether your
water system has the capacity for the treatment unit’s
requirement to perform adequately. For example, be
sure you have adequate pressure in your system for a
reverse osmosis unit.

9. Is there a shutoff system in case of malfunction?
Is there an indicator light or alarm to indicate a
problem?

Some units have shutoff systems and indicators to
prevent you from consuming untreated water.

10. Does the device require maintenance? How do I
know when maintenance is necessary?

Devices such as activated carbon units, reverse osmosis
(RO) units, iron filters, etc. require regular maintenance.
Make sure you understand the cost and effort
necessary to properly maintain the equipment. Know
how to contact company representatives if you have
any questions after the device is installed.

11. Can I install the device and perform required
maintenance myself or do I have to rely on company
service?

You may be able to save a great deal of money with
do-it-yourself equipment, but make sure the job is
done right. Your money is wasted if equipment is not
working properly. Find out if the warranty is voided if
you perform maintenance on the device.

12. What are the total costs for purchase and
maintenance, including labor for installation and
service?

Watch for hidden costs such as installation fees,
regular maintenance fees, equipment rental fees or
costs associated with disposal of reject water or spent
cartridges. Also ask about the electrical usage of the
device.

13. What is the expected lifetime of the device?
How long does the warranty last and what does it
cover?

Consider the long-term cost of replacement or repair
when making your purchase decision. Know all the
requirements to keep the warranty in effect.

These questions serve as guidelines for consulting
with water treatment equipment representatives. It
is wise to shop around and get the best deal possible
on the water treatment equipment you really need.
Always get all guarantees and promises in writing
and know how to contact the company selling you the
equipment. It is always beneficial to work with a water
professional while considering any water treatment
system.

Summary

In the past, if you lived in a rural area, you were
forced to live with whatever water supply was available,
no matter how poor the quality of water was.

Often, the only alternative was to move. We now have
methods available to treat almost any water quality
problem. We also understand more about and are more
aware of toxic effects associated with impurities in
water. As a result, health problems associated with
poor water quality can be minimized or prevented if
water testing is done on a regular basis and appropriate
measures for well maintenance and water treatment
are taken in consultation with laboratory and water
treatment professionals.

Sources

A Guide to Home Water Treatment, MSU Extension
Water Quality Bulletins-WQ219201, Michigan
State University Extension, Lansing,
Michigan, 1997.

Healthy Drinking Waters for Rhode Islanders: Ion
Exchange Treatment of Drinking Water
Supplies. Private Wells Series April 2003,
Rhode Island Department of Health and the
University of Rhode Island Cooperative
Extension Water Quality Program.

Questions to Ask When Purchasing Water Treatment
Equipment . Publication 356-480 Virginia
Cooperative Extension, College of Agriculture
and Life Sciences, Virginia Polytechnic
Institute and State University, 2009.
Available online at: http://pubs.ext.
vt.edu/356/356-480/356-480.pdf.

Saha, U., L. Sonon, D. Kissel, and R. Hitchcock. 2011.
Total Coliform and Escherichia coli Bacteria
in Georgia Private Wells: Relationships of Age
and Depth of the Wells. In: Proceeding of the
2011 Land Grant and Sea Grant National Water
Conference. January 31-February 1, 2011.
Washington DC.